In a centrifuge, substance mixtures are separated by implementation of high acceleration forces. To this end, the substance mixture is placed in a sample container, which is then driven so as to rotate in such a manner that centrifugal forces occur within the sample container to cause separating processes to take place. By this means, for instance, individual liquids may be separated from each other or solid particles from a liquid. On account of the high acceleration values, high forces act on the sample container and its contents so that sample containers must show a high degree of mechanical stability or must be stabilized.
There are various types of sample containers, for which reason adapters are used to fit the different geometries of sample containers to a centrifuge bucket. The sample containers are accommodated in the adapter and the adapter is inserted in a centrifuge bucket. The latter, in turn, is mounted on a centrifuge rotor, which is driven so as to rotate during a centrifuging operation.
It is further desirable for the walls of the sample containers used for the accommodation of samples to be as thin as possible for reasons of weight and the reduction of costs. This, however, results in a loss of stability of the sample container—often to such an extent that they are no longer self-supporting. The same problem occurs with respect to sample containers designed as bags or bag system as used, for example, for centrifuging blood. In the case of such sample containers, the adapters will also serve to support the containers and to maintain their shape.
Furthermore, increasingly larger sample containers are being used for the purpose of achieving more efficient centrifugation. Every centrifuging operation is set to a predetermined time limit, so that sample containers of the largest possible capacity are used to save batch time and reduce overall costs. Due to the high acceleration forces that occur during centrifugation, however, enormous forces are liberated, which act on both the sample container and on the adapter. As a result, the sample container and the adapter may be deformed to such an extent that they can hardly or not at all be separated from each other. Furthermore, there is the possibility of an increased risk of injury occurring during removal of the sample container, since the sample container and the adapter will have become firmly wedged together to render them less readily separable. There is also the added possibility of the deformed sample container being no longer reusable, which in turn increases the costs of the process of centrifugation. Due to the above risks, sample containers of a larger volume are usually restricted as to acceleration, which, however, is concomitant with a reduction in separation efficiency.
German Patent Application No. DE 10 2012 013 641 A1, which is incorporated herein by reference in its entirety, describes an adapter for sample containers, which has a separation or expansion joint in its side wall. This allows for expansion of the adapter for an easy removal of the sample container, which advantageously facilitates the separation of the adapter and the sample container and reduces the risk of damage to the sample container. Conversely, this also enables centrifuging of sample containers with higher volumes even at high accelerations. However, it has been seen here that during centrifugation of sample containers with more complex geometry or with attachments, such as hoses, the sample container or its attached parts can get entangled in the separation joints of the adapter so that the sample container gets damaged during centrifugation or the removal process becomes difficult. This disadvantageous effect of the separation joints can occur, for instance, while centrifuging blood bag systems, where multiple blood bags with hose connections are centrifuged in packages.
It is, therefore, an object of the present invention to provide an adapter for a sample container, which provides all the benefits of the centrifuge adapter described in German Patent Application No. DE 10 2012 013 641 A1, while, at the same time, reducing the risk of damage occurring to the sample container on account of the separation joints during centrifuging and removing.